Durability and service life of wood structures and components: State of the art

For wood material, moisture stress and biological factors like mould and decay fungi are often critical, especially in cladding and decking structures in exterior use conditions. In the future, the life time expectations and analyses of different building products will need more data on the durability of products, service life and resistance against mould and decay, not only data on wood material itself. The first step to evaluate the exposure conditions is the macroclimate conditions. The driving rains, moisture, temperature and also the solar radiation are the most important factors. The mould and decay models can be incorporated with climatic and building physic models to evaluate the effect of different exposure conditions on the durability and service life of wooden products. A basic method for service life evaluation is the factor method presented in the standards ISO 15686. For wooden components, the most important factors are wood material and coatings, design and execution of structure, exposure conditions of environment and maintenance of the wood structure and surface.